Use Of Iron(III) Complex Compounds

ABSTRACT

The present invention relates to novel therapeutic uses of iron(III) complex compounds with carbohydrates or derivatives thereof, in the preparation of a medicament for improving immune defense and/or brain performance.

The present invention relates to novel therapeutic uses of iron(III)complex compounds with carbohydrates or derivatives thereof, inparticular with dextrins or oxidation products of dextrins, inparticular in the preparation of medicaments for improving immunedefense and/or brain performance.

Iron deficiency is the most frequent trace-element deficiency worldwide.Not only does it affect children, from infants to adolescents, in thedeveloping countries, it is also observed in a significant number ofchildren in the rich, industrialised nations. For example, 28% ofteenagers in Canada show signs of iron deficiency.

The use of iron(III) oxide as an active ingredient for the treatment ofimmune deficiency syndromes, especially AIDS, is known from WO 95/35113.

Therapeutically usable iron injection preparations and processes fortheir production are known from DE 1467980.

Processes for the preparation of iron(III)-polymaltose complex compoundswhich are suitable for parenteral administration are known from U.S.Pat. No. 3,076,798.

The use of iron-carbohydrate complexes in the treatment or prophylaxisof iron deficiencies is known from WO 2004037865.

Iron complex compounds with hydrogenated dextrins for the treatment orprophylaxis of iron deficiencies are known from WO 03/087164.

Iron(III)-pullulan complex compounds and their use in the treatment orprophylaxis of iron deficiencies are known from WO 02/46241.

It is known from Baumgartner “New Aspects of Iron Therapy”, SecondFerrum Meeting, Lisbon 1994, that both the activity and the cognitiveperformance of the left hemisphere of the brain are dependent on anindividual's iron status. In that publication, Baumgartner mentions astudy by Walter, according to which iron-related anaemia significantlyleads to restricted mental and psychomotor development in children. Thecompound used in the study was iron sulfate. However, afteradministering iron sulfate for 75 days, Walter did not find anyimprovement in the mental and psychomotor development.

Other studies mentioned in Baumgartner show a significant improvement incognitive performance with iron therapy.

Baumgartner further presents clinical studies which reflect theinfluence of the iron status on the immunological functions.

Iron sulfate is known to cause, relatively frequently, unpleasantdose-dependent secondary reactions, such as gastro-intestinaldisturbances or discolouration of the teeth. Iron from iron saltcompounds is subject to the passive diffusion of free iron ions. Theiron can enter the circulation and thereby cause secondary reactions oriron poisoning. Consequently, the LD₅₀ value in white mice, at 230 mg ofiron/kg, is also relatively low. The use of iron salt compounds istherefore disadvantageous in particular when treating children, in whomiron is particularly important for the development of the brain and theimmune system.

The study of Tucker “Iron status and brain function: serum ferritinlevels associated with asymmetries of cortical electrophysiology andcognitive performance” (Am. J. Clin. Nutr. 1984; 39: 105-113), which isalso mentioned in the publication of Baumgartner, shows that brainperformance is proportional to the ferritin level.

Oski “Effect of Iron Therapy on Behavior Performance in Nonanemic,Iron-Deficient Infants”, PEDIATRICS 1983; Volume 71; 877-880, uses irondextran. The parenteral use of iron dextran is disadvantageous because adextran-induced anaphylactic shock can occur.

The inventors therefore set themselves the object of finding readilytolerable iron compounds which are suitable for improving brainperformance and immune defense in particular in children, includinginfants and adolescents.

In a study, they have been able to demonstrate that iron(III) complexcompounds with carbohydrates, in particular with polymaltose(maltodextrin), are particularly tolerable, have high patient complianceand bring about a significant improvement in immune defense and/or brainperformance. Also surprising was the fact that an early significantimprovement in immune defense and/or brain performance is found eventhough iron(III)-polymaltose complex compounds result in only a slowincrease in the ferritin level. On the basis of this result, theycompleted the present invention. The invention therefore relates to theuse of iron(III) complex compounds with carbohydrates or derivativesthereof in the preparation of a medicament for improving immune defenseand/or brain performance.

The improvement in immune defense within the scope of the inventionmeans a significant improvement in the immune responses, as is shown,for example, in a significant improvement in the lymphocyte response tophyto-haemagglutinin (PHA) using the MTT method, in an improvement inthe nitroblue tetrazolium test (MBT) using neutrophils, in animprovement in the bactericidal capacity of neutrophils (PCA) measuredby the turbidimetric method, in an improvement in the monoclonalantibodies, for example CD3, CD4, CD8 and CD56, counted, for example,using a BD flow cytometer with a simple staining method, and/or in theantibody response to measles, H. influenza and tetanus.

An improvement in brain performance within the scope of the inventionincludes in particular an improvement in cognitive functions andemotional behaviour and is expressed, for example, in an improvement inthe short-term memory test (STM), in the long-term memory test (LTM), inthe Raven progressive matrices test, in the Wechsler adult intelligencescale (WATS) and/or in the emotional coefficient (Baron EQ-i, YV test;youth version).

Iron(III) complex compounds with carbohydrates which can be usedaccording to the invention preferably include those whereincarbohydrates are selected from the group consisting of dextrans andderivatives thereof, dextrins and derivatives thereof and also pullulan,oligomers and/or derivatives thereof. Particular preference is given toiron(III) complex compounds with dextrins or oxidation products thereof.Examples of the preparation of the iron(III) complex compounds accordingto the invention are found, for example, in patent specifications DE14679800, WO 04037865 A1, U.S. Pat. No. 3,076,798, WO 03/087164 and WO02/46241 mentioned at the beginning, the totality of the disclosures ofwhich, in particular in respect of the preparation processes, is to beincorporated herein. The term “dextrins”, which are preferably usedaccording to the invention, is a collective term for various lower andhigher polymers of D-glucose units, which form during the incompletehydrolysis of starch. They can also be prepared by polymerisation ofsugars (e.g. W002083739 A2, US20030044513 A1, U.S. Pat. No. 3,766,165).The dextrins include the maltodextrins, or polymaltoses, which areprepared by enzymatic cleavage of maize or potato starch withalpha-amylase and which are characterised by the degree of hydrolysis,expressed by the DE value (dextrose equivalent). Polymaltose can also beobtained according to the invention by acid hydrolysis of dextrins. Thepreparation of the iron(III) complex compounds which can be usedaccording to the invention is generally carried out by reactingiron(II⁻) or iron(III) salts, in particular iron(III) chloride, with thedextrins, in particular polymaltose, or oxidation products of thedextrins in aqueous alkaline solution (pH>7) and then working up.Preparation in the weakly acidic pH range is also possible. However,alkaline pH values of, for example, >10 are preferred.

The pH value is preferably increased slowly, or gradually, which can beachieved, for example, by first adding a weak base, for example to a pHof about 3; further neutralisation can then be carried out with astronger base. There are suitable as the weak base, for example, alkalior alkaline earth carbonates and bicarbonates, such as sodium andpotassium carbonate or bicarbonate, or ammonia. Examples of strong basesinclude alkali or alkaline earth hydroxides, such as sodium, potassium,calcium or magnesium hydroxide.

The reaction can be promoted by heating. For example, temperatures inthe order of magnitude of from 15° C. to the boiling point can be used.It is preferred to increase the temperature gradually. For example,heating to about 15 to 70° C. can be carried out first, and then thetemperature can gradually be increased to boiling.

The reaction times are, for example, in the order of magnitude of from15 minutes to several hours, e.g. from 20 minutes to 4 hours, forexample from 25 to 70 minutes, e.g. from 30 to 60 minutes.

When the reaction has taken place, the resulting solution can be cooledto room temperature, for example, and optionally diluted and optionallyfiltered. After cooling, the pH value can be adjusted to the neutralpoint or slightly below, for example to values of from 5 to 7, byaddition of acid or base. Examples of bases which may be mentionedinclude those mentioned above for the reaction. Acids include, forexample, hydrochloric acid and sulfuric acid. The resulting solutionsare purified and can be used directly in the preparation of medicaments.However, it is also possible to isolate the iron(III) complexes from thesolution, for example by precipitation with an alcohol, such as analkanol, for example ethanol. The isolation can also be carried out byspray-drying. Purification can be carried out in the conventionalmanner, in particular for the removal of salts. This can be effected,for example, by reverse osmosis, it being possible for such a reverseosmosis to be carried out, for example, before the spray-drying orbefore the product is used directly in medicaments.

The resulting iron(III) complexes have, for example, an iron content offrom 10 to 40% wt./wt., in particular from 20 to 35% wt./wt. They aregenerally readily soluble in water. It is possible to prepare therefromneutral aqueous solutions having an iron content of, for example, from1% wt./vol. to 10% wt./vol. Such solutions can be thermally sterilised.

Regarding the preparation of iron(III)-polymaltose complex compounds,reference may be made to U.S. Pat. No. 3,076,798.

In a preferred embodiment of the invention, an iron(III)hydroxide-polymaltose complex compound is used. Theiron(III)-polymaltose complex compound preferably has a molecular weightin the range from 20,000 to 500,000 daltons, in a preferred embodimentfrom 30,000 to 80,000 daltons (determined by means of gel permeationchromatography, for example as described by Geisser et al. in Arzneim.Forsch/Drug Res. 42(11), 12, 1439-1452 (1992), paragraph 2.2.5). Aparticularly preferred iron(III) hydroxide-polymaltose complex compoundis Maltofer® from Vifor AG, Switzerland, which is availablecommercially. In a further preferred embodiment, an iron(III) complexcompound with an oxidation product of one or more maltodextrins is used.This is obtainable, for example, from an aqueous iron(III) salt solutionand an aqueous solution of the product of the oxidation of one or moremaltodextrins with an aqueous hypochlorite solution at a pH value in thealkaline range, wherein when a maltodextrin whose dextrose equivalent isfrom 5 to 37 is used and when a mixture of a plurality of maltodextrinsis used, the dextrose equivalent of the mixture is from 5 to 37 and thedextrose equivalent of the individual maltodextrins contained in themixture is from 2 to 40. The weight-average molecular weight Mw of thecomplexes so obtained is, for example, from 30 kDa to 500 kDa,preferably from 80 to 350 kDa, particularly preferably up to 300 kDa(determined by means of gel permeation chromatography, for example asdescribed by Geisser et al. in Arzneim. Forsch/Drug Res. 42(11), 12,1439-1452 (1992), paragraph 2.2.5). Reference may be made in thisconnection to WO 2004037865 A1, for example, the totality of thedisclosure of which is to be incorporated in the present application.

Regarding the preparation of iron complex compounds with hydrogenateddextrins, reference may be made to WO 03/087164.

Regarding the preparation of iron(III)-pullulan complex compounds,reference may be made to WO 02/46241.

The iron(III) hydroxide complex compounds used according to theinvention are preferably administered orally. In principle, however,they can also be administered parenterally, such as intravenously, orintramuscularly.

The daily oral dose is, for example, from 10 to 500 mg of iron/day ofuse. Administration can continue, without hesitation, over a period ofseveral months until there is an improvement in the patient's ironstatus, reflected by the haemoglobin value, the transferrin saturationand the ferritin value. Oral administration preferably takes place inthe form of a tablet, a capsule, an aqueous solution or emulsion, in theform of granules, a capsule, a gel or in the form of a sachet. Solutionsor emulsions are preferably administered, in particular to children, inthe form of syrups or juices, drops, etc. To this end, the iron(III)hydroxide-dextrin complex compounds can be brought into the suitableform of administration with conventional pharmaceutical carriers andauxiliary substances. To this end, conventional binders or glidants,diluents, disintegrators, etc. can be used.

The use according to the invention can take place in children, youngpeople and adults. It preferably takes place for the preparation of amedicament for treating children. Children include infants andadolescents or young people.

The use according to the invention proceeds in particular by improvingthe neutrophil level, the antibody level and/or the lymphocyte function,determined, for example, by the lymphocyte reaction tophytohaemagglutinin.

The use according to the invention can serve to treat patients with irondeficiency anaemia, iron deficiency without anaemia as well as patientswithout iron deficiency anaemia or iron deficiency, preferably fortreating patients with iron deficiency. This classification is dependenton the age and sex of the patient and can also vary from person toperson. Classification can be made, for example, by the haemoglobinvalue and the value for trans-ferrin saturation (%). Reference valuesfor haemoglobin, determined by flow cytometry (photometric):cyan-haemoglobin method, are listed, for example, in Charite, Institutfür Laboratoriumsmedizin and Pathobiochemie(http://www.charite.de/ilp/routine/parameter.html).

Transferrin saturation in patients without iron deficiency is generally>16%.

According to M. Wick, W. Pinggera, P. Lehmann,Eisenstoffwechsel—Diagnostik und Therapien der Anämien, 4., enlargededition, Springer Verlag Vienna 1998, all forms of iron deficiency canbe detected clinico-chemically. A reduced ferritin concentration isgenerally accompanied, by way of compensation, by increased transferrinand low transferrin saturation.

Surprisingly, improvements in immune defense and/or brain performancehave also been achieved according to the invention in patients who had anormal haematological result in respect of iron status.

The mode of action of the invention is explained and demonstrated by theexample which follows.

EXAMPLE

Using a film-coated tablet (620 mg per tablet) containing 357.0 mg of aniron(III) hydroxide-polymaltose complex compound (Maltofer®),corresponding to 100 mg of iron, a single-centre study of oral ironsupplementation in adolescents with iron deficiency, with or withoutanaemia, in comparison with a placebo group was carried out.

The aim of the comparative study was to study the effects of orallyadministered iron(III) hydroxide-polymaltose complex (100 mg of iron perday and placebo for 6 days per week for 8 months) on the immuneresponses, the haematological status, the cognitive functions and thebehavioural functions in four groups of adolescents with irondeficiency, anaemia, with iron deficiency, without iron deficiency andanaemia (iron supplementation) and a further group without irondeficiency and anaemia (placebo group).

To this end, 500 apparently healthy adolescents of both sexes agedbetween 15 and 18 were chosen at random and divided into the followinggroups using a plurality of haematological criteria.

Group Haemoglobin (g/dl) Transferrin saturation (%) A: iron deficiencyboys: 7-<11.5 <16 anaemia (IDA) girls: 7-<10.5 <16 B: iron deficiencyboys: ≧11.5 <16 (ID) girls: ≧10.5 <16 C: no iron deficiency, boys: ≧11.5≧16 no anaemia, normal girls: ≧10.5 ≧16 supplementation (NS) D: placebo,no boys: ≧11.5 ≧16 anaemia, normal girls: ≧10.5 ≧16 placebo (NP) Eachgroup consisted of 30 test subjects and there was a total of 120 testsubjects, who were divided into the above-mentioned four groups (NP, NS,ID and IDA).

Each group consisted of 30 test subjects and there was a total of 120test subjects, who were divided into the above-mentioned four groups(NP, NS, ID and IDA)

Test Process: Haematological Evaluation:

Venous blood was taken from all 120 test subjects using vacuum testtubes, and all the blood parameters were analysed in a Sysmax bloodtest. The serums were separated from the blood samples and stored at−20° C. Serum samples were subjected to SFe and TIBC determinations bystandard methods (NIN-Manual 1983). TS was calculated from SFe and TIBCand given as a percentage. Serum ferritin analyses were carried outusing an “enzyme linked immuno sorbent assay” (ELISA).

Serum folate and cyanacobalamin (B12) were determined by standardmethods.

Immune Responses:

Neutrophils and lymphocytes were separated from fresh blood samples bythe single-stage double density gradient method, and the followingimmunological assays were carried out for all 120 test subjects:

-   -   lymphocyte response to phytohaemagglutinin (PHA) using the MTT        method;    -   nitroblue tetrazolium test (MBT) using neutrophils;    -   bactericidal capacity of the neutrophils (BCA) measured by the        turbidimetric method.

Using fresh samples of whole blood, counts of the monoclonal antibodiesCD3, CD4, CD8 and CD56 were carried out using a BD flow cytometer by thesingle-staining method and expressed as a percentage for all 120subjects.

The following tests were carried out using serum samples from all 120test subjects:

-   -   antibody responses to measles, flu viruses and tetanus;    -   C-reactive protein using a semi-quantitative method.

Cognitive Functions and Emotional Behaviour

The cognitive functions and the emotional behaviour of the 120 testsubjects were determined in accordance with the most frequently usedtests and according to established methods:

-   1. short-term memory test (STM)-   2. long-term memory test (LTM)-   3. Raven progressive matrices (RPM)-   4. Wechsler adult intelligence scale (WAIS)-   5. emotional quotient (Baron EQ-i; YV test; youth version).

Evaluation of Achievement in School

The achievements of the 120 test subjects in school were determinedindividually by means of a school achievement test.

Anthropometric evaluations, physical examinations, urine and stoolexaminations were carried out by standard methods.

Statistical Evaluation:

Comparison of the average values of the parameters over successive timeperiods gave a picture of the effect of the treatment. The nature of theevaluation meant that a repeated measures design was required. For eachparameter there were three sets of observations, which were allcorrelated. Consequently, the repeated measures test is the suitablemeans, and the statistical analysis was carried out using SPSS software.The method tests the significance of the parameter values over theduration (points of time) between the groups and, if present,interaction between duration and group. Multiple comparisons betweendifferent groups were carried out automatically by the repeated measurestest with the aid of LSD (least significance difference test).

Results

Advantageous effects were found in all the tests carried out, namely inrespect of the haematological status, the immune status, the cognitivefunction and the emotional behaviour.

Significant increments were found for all iron-related haematologicalparameters from the baseline to four months and again from four monthsto eight months of the supplementation in all groups to which the ironpreparation was given, namely the group with iron deficiency with (IDA)or without (ID) anaemia and the group with normal haematology whichreceived supplementation (NS).

There was a significant increase in the lymphocyte response tophytohaemagglutinin, bacterial killing by neutrophil assay, nitrobluetetrazolium test and the levels of antibodies towards measles andHaemophilus influenza in the three groups with supplementation (IDA, ID,NS) for the periods 0 to 4 months and 4 to 8 months. For antibodies totetanus, the difference between the baseline and 8 months wassignificant for these three groups.

The cognitive performance improved from the baseline to four months andfrom 4 to 8 months in all the tests, including SAT, with the exceptionof EQ.

These increments in haematological, immunological and cognitivefunctions have important clinical significance. By the regularadministration of an iron(III) hydroxide-polymaltose complex, immunedefense and brain performance can be improved, with enormous advantagesto society.

1-12. (canceled)
 13. A method of increasing brain performance in a humanpatient, the method consisting of administering to a human patient nothaving iron deficiency anemia or iron deficiency a medication consistingof an iron (III) compound selected from the group consisting of iron(III) polymaltose and an iron (III) maltodextrin complex, the iron (III)maltodextrin complex comprising a complex of an oxidation product of oneor more maltodextrins with iron (III), relative to a human patient notso administered.
 14. A method of improving brain performance in a humanpatient consisting of administering to a human patient not having aniron deficiency anemia or an iron deficiency a medication consisting ofan iron (III) compound selected from the group consisting of iron (III)polymaltose and an iron (III) maltodextrin complex, the iron (III)maltodextrin complex comprising a complex of an oxidation product of oneor more maltodextrins with iron (III), wherein the human patient may beof any age.
 15. The method of claim 13, wherein the iron (III)polymaltose complex has a molecular weight (M_(w),) of 20,000 to 500,000Daltons.
 16. The method of claim 13, wherein the iron (III) polymaltosecomplex has a molecular weight (M_(w)) of 30,000 to 80,000 Daltons. 17.The method of claim 14, wherein the iron (III) polymaltose complex has amolecular weight (M_(w)) of 20,000 to 500,000 Daltons.
 18. The method ofclaim 14, wherein the iron (III) polymaltose complex has a molecularweight (M_(w)) of 30,000 to 80,000 Daltons.